Ford Sierra Sapphires were one of the most common everyday cars of the '80s, with the vast numbers produced parts are readily available and cheap-at the moment. They remain a reliable family car suitable for everyday use on a budget. You should buy carefully as sierras were one of the last Fords to suffer badly with rust.
Pinto engined cars are thisty, later DOHC engines better on fuel but more fragile. 1.8 turbo diesels are a good performance/economy compromise.